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Finding the Fourth Proportional to 93.10, 139.65 and 85.90

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Solution

The fourth proportional to 93.10, 139.65 and 85.90 is: 128.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.10 : 139.65 = 85.90 : x
  2. Step 2: Convert to fraction form
    93.10/139.65 = 85.90/x
  3. Step 3: Cross multiply
    93.10x = 139.65 × 85.90
  4. Step 4: Simplify right side
    93.10x = 11,995.94
  5. Step 5: Solve for x
    x = 11,995.94/93.10
  6. Step 6: Final answer
    x = 128.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.